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Discussion Starter #1
I would like to have you guys opinions. I intentionally built my match rifle with a tight neck but I have 2 other customs that I have to turn the necks on that I didn't plan to be tight neck chambers. These were cut with PT&G reamers. I'm thinking about opening up the necks to accept factory cases. But, they shoot so well that I'm really hesitating to touch them. This is just the two varminters, not for the match rifle.

What would you do?

I learned to turn necks for my match rifle and I have the equipment. Neck turning tools, turning mandrals, expanding mandrals, measuring tools, ect. I even have bushing dies for these. It would just be nice to shoot factory ammo if I wanted. I know its a one and done deal and its not really that much work.

These are varmint weight rifles. One is in 243 and the other is 22-250AI. I use Lapua brass for all of these.

Thanks for your thoughts.
 

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What level of accuracy are you expecting? I have several factory chambered varmint caliber rifles that shoot 0.5MOA and less with decent handloads and will do the same with their favored factory loads.
 

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Discussion Starter #3
Thats a good question. Right now, with the tighter neck chambers both rifles will shoot one hole groups. 1/4 to 1/2 moa. I would think and hope that they would shoot that well or nearly so with a little larger neck. Maybe I'm not being realistic? Like I said, I'm really hesitant to change anything, just trying to streamline my loading process and have the option of shooting factory ammo.

I doubt that I'll change anything. I already have a 3 die set of Redding bushing dies for each of them, with a competition seater and a body die. And I already have neck turning equipment. Actually, I bought a tool for each caliber so I can adjust the tool, lock it down, and not have to readjust them. Neck turning should be a once and done job although I turn them again a 2nd time after they have been fired about 5 times. I'll get a little material off on that 2nd time, so I guess the brass does flow a little.

Neck turning, once set up, is not that big of a job. I was just thinking about eliminating a step from my process. I guess I would be smart to just leave well enough alone!
 

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I shot a .261x 47D TNT rifle in benchrest until somebody broke in and apparently wanted the gun more than me. There CAN be advantages of neck turning but if the rifle isn't set up for it, it doesn't work very well and usually accuracy is not improved. To get the real advantages of neck turning in a benchrest environment, you have to index the cases and put them in the chamber accordingly. Obviously this is after fireforming. Then everything fits as intended but doing it this way means there is no case resizing. Just knock the primer out, reprime, reload and shoot again. I often reloaded cases while waiting to shoot with a Wilson set of hand dies. You might give no sizing a case a try to see just how good a fit you're getting. A true Tight Neck Turkey rifle does not require a sizing die to reload, and frankly, resizing destroys the advantages of a TNT chambering. The idea behind TNT is that the case becomes an exact duplicate of the chamber which resizing destroys. But you have to ask yourself, what advantages and improvements are you going to get? If you're already shooting the one hole groups, there's not much to be had from the process.
Assuming that the chamber has been cut and throated accordingly, you should be neck sizing .002 smaller than the neck in the chamber. What numbers did the gunsmith that cut the barrel give you to cut to? For a Tight Neck chamber, it's not an arbitrary number, it's a VERY specific cut. When I cut mine, I got the neck cutter to cut .001 smaller and then hand cut the rest of it with 000 steel wool. Yeah, it takes a long time but the cases last forever as there is no growth in any direction.
 

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Discussion Starter #5
My long range rifle was built with an intentional tight neck. I run .0015 neck clearance. I do size the necks after they are fired but I probably don't have to. I've expiermented with neck turning in factory rifles and found that it helps very little or even none at all. The increased neck clearance even seems to shorten the brass life.

The 2 rifles that I posted about are Remington actions with a little truing done and rebarreled with Krieger barrels. I wanted a accurate varmint rifle but didn't plan to neck turn. The necks are tight enough that I have to turn them. I don't have to remove much material but new brass won't chamber nor will factory ammo. I didn't plan for that and have thought about opening up the necks. But they shoot so well that I'm hesitant to do anything to them. I doubt I'll change anything.
 

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Perhaps......

........sorting your virgin brass, by neck-wall thickness runout, will give a more uniform chamber/neck fit.

Long ago, I started sorting new brass this way......as weights varied so little.

Kevin
 

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I'm not all that sure I understand your motivation, but since you asked for comments I'll add mine. Unless you are shooting colony varmints (prairie dogs and such) you probably don't need all that much ammo. Neck turning is a one time event. Once you've done it for a batch of cases you're good to go. I guessing from what you said you already have cases for the two varmint rifles.
You don't say if you have the machines and skills to open up the necks, so if you don't you will have to pay. Unless, of course, you have a friend who will do it for free. Once you do this your tight neck brass will deteriorate quickly. While it will still shoot, doing so in a larger chamber will work the necks quite a bit more and they will begin to split. Also, I don't know why an experienced reloader would choose factory ammo over handloads, but you have your reasons. I doubt I would do it on these barrels, but it might be an idea on the eventual replacements.

Rick
 

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Discussion Starter #8
I probably won't do anything to these barrels. After all, I have everything I need to make them work. And they shoot very well. Thanks for the replys everyone.
 

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To turn or not to turn depends on the neck wall thickness uniformity of the brass.

For my own edification, I experimented and compared results between turned and not turned brass, using a factory Rem 700 VARMINT in 223.

This was a factory barrel, mind you. And, to get a clearer data set I arranged the rounds in 4 groups according to runout ranging from .0005 to .001, .002 to .003, .004 to .005, and .006 to.007

I was using V-max 50± .2 gn bullets with WS2 (tungsten disulfide) coatings, N133 powder and Fed 205 match primers. Previous experience with WS2 showed there was match grade consistency in group size for over 70 rounds w/o cleaning, once the barrel was "primed" with 3 or 4 fouling shots. So, there was no cleaning between groups. In fact the groups were shot "round robin" to further negate barrel fouling between groups.

In short, what I discovered was (100 yard) group sizes ranged from 3/4 MOA down to approx 3/8 MOA as runout got smaller...TO A POINT!

As runout decreased, the change in group size from the .006 to .007 to under .002 group diminished rapidly at first and was less change as runnout approached .002.

I reran the experiment and concluded that in that particular factory rifle, there was little benefit to runnout less than .002".

So, as long as a brass source can maintain neck wall thickness uniformity to .002" or less, the need to turn cases for a VARMINT barrel wasn't practical. And, can factory barrels appreciate ammo with .002 vs. .007+ runnout? ABSOLUTELY*!

Aware that neck turning for a factory chamber results in increased working of the necks and subsequent work hardening leading to split cases (if not periodically annealed), I counter that with volume of cases. For my 223 I bought brass in 500 pc batches from the same lot. By spreading the work load over (for me) a substantial number of cases decreases the work hardening of any one piece of brass.

To keep track (for annealing reasons) I would sketch a note on a piece of paper noting the number of firings for that box of cases. Once the cases had been reloaded/fired a certain number of times, they would get trimmed and annealed - ready to reload again (and again). I'm happy with my case life in factory barrels; "not a problem" for me, at least.

Case in point: Several shooters have noticed the exemplary neck wall uniformity of some case manufactures: Lapua comes to mind. In fact, some have specified custom tight neck reamer dimensions with (Lapua) cases in mind - in order to avoid ever having to turn the cases for their varmint rifles. However, match cases typically all get turned to specification regardless of manufacture in order to eliminate any unsuspected variation - however slight - one might experience with any brass source.

.
 

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Discussion Starter #10
Thanks for taking the time to post the results of your work. The results were interesting, especially about the diminishing returns under .002.

These 2 rifles were not planned to have tight necks but they ended up being tight enough that I have to turn the necks for them. I don't have to remove very much material but an unturned case won't chamber. They shoot so well that I have decided to leave them as is. I only have to make one light cut and its done.
 

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Thanks for taking the time to post the results of your work. The results were interesting, especially about the diminishing returns under .002.

These 2 rifles were not planned to have tight necks but they ended up being tight enough that I have to turn the necks for them. I don't have to remove very much material but an unturned case won't chamber. They shoot so well that I have decided to leave them as is. I only have to make one light cut and its done.
Yes, I too have experienced some exceptionally snug chambers in factory rifles: the first being a Ruger in 6PPC, and my factory 223 heavy varmint bbl that came with my Savage LRVP.

And, you're right: once the cases are turned, except perhaps for annealing and trimming occasionally, the necks don't ever have to be turned again. And so, (for me) that runnout experiment proved to me that uniform neck wall thickness is as important in a factory rifle barrel accuracy as it is in a custom "tight neck" or "fitted neck" chamber. (That ol Rem 700 varmint would drill sub 1/2 MOA (center to center) 5-shot one-hole groups consistently. I shoulda kept that gun "as is", but I had Hart rebarrel it in 6BR stainless (.920" @ the muzzle). No complaints on the 6BR, but even my Savage LRVP is shaded by that factory Rem varmint rig. (However, my wife Ami's Savage BVSS re-barreled with a factory fluted stainless in 223 keeps 5 in a group I can cover with a nickle at 200 yards with turned cases. (Runout and seating depth were two of my bigger "AH-HA!" moments when I got interested in precision reloading.)
 

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Let’s look at this from a different direction. You might measure your factory ammo and run a throating reamer into your barrels. In that way that too tight factory ammo would fit. Just don’t open it very much as Rick Fox pointed out you don’t want the brass to work very much from fired and then sized brass. The fact that bench resters get the mileage they get out of a case is due to the fact they move the brass very little. Your original post makes it seem you are trying to get three fifes to shoot better with factory as well as reloaded ammo.
 
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